JP2001279495A - Internal combustion engine piston made of aluminum alloy - Google Patents

Internal combustion engine piston made of aluminum alloy

Info

Publication number
JP2001279495A
JP2001279495A JP2000089757A JP2000089757A JP2001279495A JP 2001279495 A JP2001279495 A JP 2001279495A JP 2000089757 A JP2000089757 A JP 2000089757A JP 2000089757 A JP2000089757 A JP 2000089757A JP 2001279495 A JP2001279495 A JP 2001279495A
Authority
JP
Japan
Prior art keywords
anodic oxide
oxide film
aluminum alloy
internal combustion
combustion engine
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP2000089757A
Other languages
Japanese (ja)
Inventor
Hajime Miyasaka
一 宮坂
Ryotaro Takada
亮太郎 高田
Yuji Marui
勇治 丸井
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Honda Motor Co Ltd
Original Assignee
Honda Motor Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Honda Motor Co Ltd filed Critical Honda Motor Co Ltd
Priority to JP2000089757A priority Critical patent/JP2001279495A/en
Publication of JP2001279495A publication Critical patent/JP2001279495A/en
Pending legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05C—INDEXING SCHEME RELATING TO MATERIALS, MATERIAL PROPERTIES OR MATERIAL CHARACTERISTICS FOR MACHINES, ENGINES OR PUMPS OTHER THAN NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES
    • F05C2201/00—Metals
    • F05C2201/02—Light metals
    • F05C2201/021—Aluminium

Landscapes

  • Pistons, Piston Rings, And Cylinders (AREA)

Abstract

PROBLEM TO BE SOLVED: To provide an internal combustion engine piston made of aluminum alloy, capable of reducing sliding resistance. SOLUTION: The internal combustion engine piston 10 made of aluminum alloy has streaks 22 on the external surface 21a of a skirt section 20. An anode oxidation film 50 is electrolytically plated on the external surface 21a. The electrolytic solution contains phosphate and fluoride compounds, and fine pores 52 of the anode oxidation film 50 are impregnated with thermosetting resin 54. The anode oxidation film 50 can be formed in such a way that it maintains the shape of the streaks 22, and makes the film surface 21 nearly equal to that of the streaks 22.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【発明の属する技術分野】本発明はアルミ合金で鋳造し
た内燃機関用のピストンに関する。The present invention relates to a piston for an internal combustion engine cast from an aluminum alloy.

【０００２】[0002]

【従来の技術】自動車の燃費やエンジン出力を向上させ
るためにピストンの摺動抵抗を減少させる方法が知られ
ている。このピストンの一例として、特開平１１−３３
６８９５号公報「ピストン及びピストンの加工方法」が
提案されている。この技術はピストンのスカート部に陽
極酸化皮膜を形成し、陽極酸化皮膜に化成処理皮膜を形
成することで、ピストンの摺動抵抗を減少させるもので
ある。2. Description of the Related Art There is known a method of reducing the sliding resistance of a piston in order to improve the fuel efficiency and engine output of an automobile. As an example of this piston, Japanese Patent Application Laid-Open No. 11-33
No. 6895, "Piston and Piston Processing Method" has been proposed. This technique reduces the sliding resistance of the piston by forming an anodized film on the skirt portion of the piston and forming a chemical conversion film on the anodized film.

【０００３】一方、摺動抵抗を減少させるために、ピス
トンのスカート部に条痕を形成する方法も知られてお
り、条痕を上記公報の技術と併用すること（すなわち、
条痕に皮膜を被せること）で摺動抵抗をより減少するこ
とができる。以下、条痕に皮膜を被せた例を、次図で詳
しく説明する。[0003] On the other hand, a method of forming a streak on a skirt portion of a piston to reduce sliding resistance is also known.
Sliding resistance can be further reduced by covering the streak with a film). Hereinafter, an example in which a film is covered on a streak will be described in detail with reference to the following drawings.

【０００４】図１４（ａ），（ｂ）は従来の内燃機関用
ピストンのスカート部の断面図であり、（ａ）はスカー
ト部に条痕を形成した例を示し、（ｂ）は条痕に皮膜を
被せた例を示す。（ａ）において、ピストン１３０のス
カート部１３１に条痕１３２・・・（・・・は複数個を示す）
を形成する。条痕１３２・・・の凹部１３３・・・を深さＨに
一定に確保することで、スカート部１３１全体に油膜を
均一に保持することができる。このため、ピストン１３
０の摺動抵抗を減少することができる。（ｂ）におい
て、ピストン１３０のスカート部１３１に条痕１３２を
形成した、スカート部１３１に陽極酸化皮膜１３５を形
成し、陽極酸化皮膜１３５に化成処理皮膜１３６を形成
する。FIGS. 14 (a) and 14 (b) are cross-sectional views of a skirt portion of a conventional piston for an internal combustion engine. FIG. 14 (a) shows an example in which a streak is formed on the skirt portion, and FIG. The following shows an example in which a film is covered. In (a), a streak 132 is formed on a skirt portion 131 of a piston 130.
To form By keeping the recesses 133 of the streaks 132 at a constant depth H, the oil film can be uniformly held over the entire skirt portion 131. Therefore, the piston 13
0 sliding resistance can be reduced. 2B, a striation 132 is formed on the skirt 131 of the piston 130, an anodic oxide film 135 is formed on the skirt 131, and a chemical conversion coating 136 is formed on the anodic oxide film 135.

【０００５】[0005]

【発明が解決しようとする課題】しかし、陽極酸化皮膜
１３５及び化成処理皮膜１３６を形成することで、条痕
１３２の凹部１３３が埋め込まれた状態になる。このた
め、化成処理皮膜１３６の凹部１３７は、条痕の凹部と
比べて深さＨ１が浅くなる。加えて、化成処理皮膜１３
６の凹部１３７は深さが不均一なので、スカート部１３
１全体に油膜を均一に保持することはできない。従っ
て、条痕１３２・・・に皮膜１３５，１３６を被せても、
ピストン１３０の摺動抵抗を大きく減らすことはできな
い。However, by forming the anodized film 135 and the chemical conversion film 136, the recess 133 of the streak 132 is buried. For this reason, the concave portion 137 of the chemical conversion coating 136 has a shallower depth H1 than the concave portion of the striation. In addition, chemical conversion coating 13
6 has a non-uniform depth, the skirt 13
1 cannot maintain an oil film uniformly. Therefore, even if the coatings 135 and 136
The sliding resistance of the piston 130 cannot be greatly reduced.

【０００６】そこで、本発明の目的は、ピストンの摺動
抵抗を十分に減少させることができるアルミ合金製内燃
機関用ピストンを提供することにある。An object of the present invention is to provide a piston for an aluminum alloy internal combustion engine that can sufficiently reduce the sliding resistance of the piston.

【０００７】[0007]

【課題を解決するための手段】上記目的を達成するため
に本発明の請求項１は、スカート部の外表面に条痕を形
成したアルミ合金製内燃機関用ピストンであって、前記
スカート部の外表面に、りん酸塩並びにふっ化物を混合
した電解液で陽極酸化皮膜を被せ、この陽極酸化皮膜の
微細な孔に潤滑剤を含浸させたことを特徴とする。In order to achieve the above object, a first aspect of the present invention is an aluminum alloy internal combustion engine piston having a streak formed on an outer surface of a skirt portion, wherein the skirt portion has An anodic oxide film is coated on the outer surface with an electrolytic solution containing a mixture of phosphate and fluoride, and fine pores of the anodic oxide film are impregnated with a lubricant.

【０００８】電解液にりん酸塩並びにふっ化物を混合す
ることで、陽極酸化皮膜を平坦に形成する。これで、陽
極酸化皮膜を条痕の形状に倣わせて形成して、陽極酸化
皮膜の表面を条痕と略同じ形状にする。このため、スカ
ート部の条痕と同じ量の油膜を陽極酸化皮膜の表面に保
持する。加えて、りん酸塩には陽極酸化皮膜の微細な孔
の孔径を大きくする作用があるので、微細な孔に多量の
潤滑剤を含浸させ、その潤滑剤を孔内に確実に固着させ
る。The anodic oxide film is formed flat by mixing a phosphate and a fluoride into the electrolytic solution. Thus, the anodic oxide film is formed so as to follow the shape of the streak, and the surface of the anodic oxide film is made substantially the same shape as the streak. For this reason, the same amount of oil film as the streak of the skirt portion is held on the surface of the anodic oxide film. In addition, since phosphate has an effect of increasing the diameter of the fine pores of the anodic oxide film, a large amount of lubricant is impregnated into the fine pores, and the lubricant is securely fixed in the pores.

【０００９】請求項２において、潤滑剤はふっ素系樹脂
であることを特徴とする。ふっ素系樹脂は耐摩耗性や耐
熱性に優れており、ピストンのような高温状態で使用す
る部材に好適である。According to a second aspect of the present invention, the lubricant is a fluororesin. Fluorine-based resin has excellent wear resistance and heat resistance, and is suitable for a member used in a high temperature state such as a piston.

【００１０】[0010]

【発明の実施の形態】本発明の実施の形態を添付図に基
づいて以下に説明する。図１は本発明に係るアルミ合金
製内燃機関用ピストン（第１実施の形態）の斜視図であ
る。アルミ合金製内燃機関用ピストン１０は、Ｓｉ（シ
リコン）系アルミニウム合金で形成した部材であって、
ピストン頭部１２にピストンリング溝１３，１４及びオ
イルリング溝１５を形成し、オイルリング溝１５の下側
に一対のスカート部２０，２５を形成し、スカート部２
０，２５の外表面２１ａ（スカート部２５の外表面は図
示しない）に条痕２２を形成し、一対のスカート部２
０，２５の間に一対のピンボス部３５，３７（ピンボス
部３７は図２参照）を形成した部材である。Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a perspective view of an aluminum alloy internal combustion engine piston (first embodiment) according to the present invention. The aluminum alloy internal combustion engine piston 10 is a member formed of a Si (silicon) -based aluminum alloy,
Piston ring grooves 13, 14 and oil ring groove 15 are formed in piston head 12, and a pair of skirt portions 20, 25 are formed below oil ring groove 15, and skirt portion 2 is formed.
A streak 22 is formed on the outer surface 21a of the pair of skirts 2 (the outer surface of the skirt 25 is not shown).
This is a member in which a pair of pin boss portions 35 and 37 (see FIG. 2 for the pin boss portion 37) are formed between 0 and 25.

【００１１】スカート部２０，２５は、条痕２２を形成
した外表面２１ａに、りん酸塩並びにふっ化物を混合し
た電解液で陽極酸化皮膜（特殊な陽極酸化皮膜）５０，
５０を被せ、特殊な陽極酸化皮膜５０の微細な孔に潤滑
剤（図４に示す）を含浸させた部材である。なお、陽極
酸化皮膜５０を被せた領域を「網目」で示す。The skirt portions 20 and 25 are formed on the outer surface 21a on which the streaks 22 are formed with an anodic oxide film (special anodic oxide film) 50, using an electrolytic solution containing a mixture of phosphate and fluoride.
50 is a member in which the fine pores of the special anodic oxide film 50 are impregnated with a lubricant (shown in FIG. 4). The area covered with the anodic oxide film 50 is indicated by “mesh”.

【００１２】図２は図１の２矢視図であり、この図でア
ルミ合金製内燃機関用ピストンの形状を詳しく説明す
る。アルミ合金製内燃機関用ピストン１０は、コンロッ
ド（図示しない）側から見たときに、一対のスカート部
２０，２５を対向する一対で構成し、これら一対のスカ
ート部２０，２５の対向する端部（一端）２０ａ，２５
ａ同士を壁部３０で連結し、スカート部２０，２５の対
向する端部（他端）２０ｂ，２５ｂ同士を壁部３２で連
結することで、これら壁部３０，３２とスカート部２
０，２５とで略矩形を形成させ、且つ壁部３０，３２の
中央にピンボス部３５，３７を膨出形成した部材であ
る。FIG. 2 is a view taken in the direction of the arrow 2 in FIG. 1. The shape of the aluminum alloy internal combustion engine piston will be described in detail with reference to FIG. When viewed from the connecting rod (not shown) side, the piston 10 for an aluminum alloy internal combustion engine includes a pair of skirt portions 20 and 25 that are opposed to each other, and opposed end portions of the pair of skirt portions 20 and 25. (One end) 20a, 25
a are connected to each other by the wall portion 30 and the opposite ends (the other ends) 20b and 25b of the skirt portions 20 and 25 are connected to each other by the wall portion 32, so that the wall portions 30 and 32 and the skirt portion 2 are connected to each other.
0 and 25 are members having a substantially rectangular shape and pin bosses 35 and 37 bulging at the centers of the walls 30 and 32.

【００１３】加えて、アルミ合金製内燃機関用ピストン
１０は、壁部３０，３２がスカート部２０，２５に交わ
る部位（すなわち、スカート部２０，２５の一端２０
ａ，２５ａ及び他端２０ｂ，２５ｂ）において、これら
の部位の内壁４０〜４３を円弧状に形成し、スカート部
２０，２５の肉厚ｔ１を壁部３０，３２の肉厚ｔ２より
薄く設定した。In addition, the aluminum alloy internal combustion engine piston 10 has a portion where the wall portions 30 and 32 intersect with the skirt portions 20 and 25 (that is, one end 20 of the skirt portions 20 and 25).
a, 25a and the other ends 20b, 25b), the inner walls 40 to 43 of these portions are formed in an arc shape, and the thickness t1 of the skirt portions 20, 25 is set smaller than the thickness t2 of the wall portions 30, 32. .

【００１４】スカート部２０，２５の対向する一端２０
ａ，２５ａを壁部３０で連結し、他端２０ｂ，２５ｂを
壁部３２で連結することで、壁部３０，３２及びスカー
ト部２０，２５で略矩形を形成する。このため、スカー
ト部２０，２５の幅Ｗをピンボス部３５，３７の幅Ｗ１
より小さくすることができる。従って、スカート部２
０，２５を幅狭まとすることで、アルミ合金製内燃機関
用ピストン１０の軽量化を図ることができる。また、ス
カート部２０，２５の肉厚ｔ１を壁部３０，３２の肉厚
ｔ２より薄く設定したので、アルミ合金製内燃機関用ピ
ストン１０をより軽量にすることができる。Opposite ends 20 of skirt portions 20 and 25
a and 25a are connected by the wall 30 and the other ends 20b and 25b are connected by the wall 32, so that the walls 30, 32 and the skirts 20, 25 form a substantially rectangular shape. Therefore, the width W of the skirt portions 20 and 25 is set to the width W1 of the pin boss portions 35 and 37.
Can be smaller. Therefore, the skirt 2
By making 0 and 25 narrower, the weight of the aluminum alloy piston 10 for an internal combustion engine can be reduced. Further, since the thickness t1 of the skirt portions 20 and 25 is set smaller than the thickness t2 of the wall portions 30 and 32, the aluminum alloy internal combustion engine piston 10 can be made lighter.

【００１５】一方、スカート部２０，２５及び壁部３
０，３２で略矩形を形成することにより、スカート部２
０，２５を壁部３０，３２で補強することができる。従
って、スカート部２０，２５の剛性を高めることができ
る。また、壁部３０，３２がスカート部２０，２５に交
わるスカート部の一端２０ａ，２５ａ及び他端２０ｂ，
２５ｂの内壁４０〜４３を円弧状に形成したので、スカ
ート部の一端２０ａ，２５ａ及び他端２０ｂ，２５ｂに
応力が集中することを防ぐことができる。従って、スカ
ート部２０，２５の剛性をより高めることができる。On the other hand, the skirts 20, 25 and the wall 3
By forming a substantially rectangular shape at 0, 32, the skirt 2
0 and 25 can be reinforced by walls 30 and 32. Therefore, the rigidity of the skirt portions 20, 25 can be increased. Also, one end 20a, 25a and the other end 20b of the skirt portion where the wall portions 30, 32 intersect with the skirt portions 20, 25,
Since the inner walls 40 to 43 of the 25b are formed in an arc shape, it is possible to prevent stress from being concentrated on one end 20a, 25a and the other end 20b, 25b of the skirt. Therefore, the rigidity of the skirt portions 20 and 25 can be further increased.

【００１６】一対のスカート部２０，２５は、幅Ｗ及び
長さＬ（図１に示す）の網目で示した外表面２１ａに条
痕２２・・・（図１に示す）を形成し、外表面２１ａに特
殊な陽極酸化皮膜５０，５０を被せ、特殊な陽極酸化皮
膜５０，５０の微細な孔に潤滑剤を含浸させたものであ
る。なお、特殊な陽極酸化皮膜及び潤滑剤については図
４でさらに詳しく説明する。The pair of skirt portions 20 and 25 form streaks 22... (Shown in FIG. 1) on an outer surface 21a shown by a mesh having a width W and a length L (shown in FIG. 1). The surface 21a is covered with special anodic oxide films 50, 50, and the fine pores of the special anodic oxide films 50, 50 are impregnated with a lubricant. The special anodic oxide film and lubricant will be described in more detail with reference to FIG.

【００１７】図３は図１の３矢視図であり、スカート部
２０，２５の下端２３，２８（下端２８は図１に示す）
をピンボス部３５，３７の下端３６，３８より延した状
態を示す。スカート部２０，２５の下端２３，２８をピ
ンボス部３５，３７の下端３６，３８より延すことによ
り、アルミ合金製内燃機関用ピストン１０がシリンダ内
を移動している際に、スカート部２０，２５をシリンダ
に接触させることでピストン１０の姿勢を正規の状態に
容易に保つことができる。FIG. 3 is a view taken in the direction of arrow 3 in FIG. 1, and the lower ends 23 and 28 of the skirt portions 20 and 25 (the lower end 28 is shown in FIG. 1).
Is extended from the lower ends 36, 38 of the pin boss portions 35, 37. By extending the lower ends 23 and 28 of the skirt portions 20 and 25 from the lower ends 36 and 38 of the pin boss portions 35 and 37, when the aluminum alloy internal combustion engine piston 10 moves in the cylinder, the skirt portions 20 and 25 are moved. By bringing the cylinder 25 into contact with the cylinder, the posture of the piston 10 can be easily maintained in a normal state.

【００１８】図４は本発明に係るアルミ合金製内燃機関
用ピストンの特殊な陽極酸化皮膜の表面を拡大した断面
図である。なお、潤滑剤５４として熱硬化性樹脂を使用
した例を説明する。特殊な陽極酸化皮膜５０は、膜厚ｔ
３が略一定で皮膜面２１を平坦に形成し、皮膜面２１に
微細な孔５２・・・（・・・は複数個を示す。以下同様。）を
備えたものである。孔５２・・・は孔径ｄ１が比較的大き
い孔である。このため、孔５２・・・に十分な量の潤滑剤
（熱硬化性樹脂）５４を含浸することができ、含浸した
熱硬化性樹脂５４を孔５２・・・内に確実に固着すること
ができる。FIG. 4 is an enlarged sectional view of the surface of a special anodic oxide film of the piston for an aluminum alloy internal combustion engine according to the present invention. An example in which a thermosetting resin is used as the lubricant 54 will be described. The special anodic oxide film 50 has a thickness t
3 is substantially constant, the coating surface 21 is formed flat, and the coating surface 21 is provided with fine holes 52... The holes 52 are holes having a relatively large hole diameter d1. Therefore, a sufficient amount of lubricant (thermosetting resin) 54 can be impregnated in the holes 52..., And the impregnated thermosetting resin 54 can be securely fixed in the holes 52. it can.

【００１９】このため、熱硬化性樹脂５４を陽極酸化皮
膜５０の微細な孔５２・・・に固着させることで、陽極酸
化皮膜５０で耐摩耗性を高めるとともに、潤滑剤で摺動
抵抗を減らすことができる。加えて、特殊な陽極酸化皮
膜５０は、皮膜面２１を平坦にすることで、摺動抵抗を
さらに減らすことができる。For this reason, by fixing the thermosetting resin 54 to the fine holes 52 of the anodized film 50, the anodized film 50 enhances the wear resistance and the lubricant reduces the sliding resistance. be able to. In addition, the special anodic oxide film 50 can further reduce the sliding resistance by making the film surface 21 flat.

【００２０】図５は図３の５−５線断面図である。特殊
な陽極酸化皮膜５０は、電解液にりん酸塩並びにふっ化
物を混合することで、Ｓｉを溶かして平坦に形成するこ
とができる。これで、陽極酸化皮膜５０を条痕２２の形
状に倣わせて形成して、陽極酸化皮膜５０の表面を条痕
２２と略同じ形状にすることができる。すなわち、条痕
２２の凹部深さＨを５μｍに形成すると、陽極酸化皮膜
５０の凹部深さＨ３を５μｍに形成することができ、極
酸化皮膜５０の凹部深さＨ３を、条痕２２の凹部深さＨ
と同じ（又は略同じ）にすることができる。このため、
スカート部２０の条痕２２と同じ量の油膜を陽極酸化皮
膜５０の表面に保持することができる。従って、アルミ
合金製内燃機関用ピストン１０の摺動抵抗を低減するこ
とができる。FIG. 5 is a sectional view taken along line 5-5 of FIG. The special anodic oxide film 50 can be formed flat by dissolving Si by mixing phosphate and fluoride into the electrolytic solution. Thus, the anodic oxide film 50 can be formed so as to follow the shape of the streaks 22, and the surface of the anodic oxide film 50 can be made substantially the same shape as the streaks 22. That is, when the depth H of the recess of the streak 22 is 5 μm, the depth H3 of the recess of the anodic oxide film 50 can be formed at 5 μm. Depth H
(Or substantially the same). For this reason,
The same amount of oil film as the streaks 22 of the skirt portion 20 can be held on the surface of the anodic oxide film 50. Accordingly, the sliding resistance of the aluminum alloy internal combustion engine piston 10 can be reduced.

【００２１】以下、図６で普通の陽極酸化皮膜の形成方
法を比較例として説明する。図６（ａ）〜（ｃ）は内燃
機関用ピストンのスカート部に普通の陽極酸化皮膜を形
成した比較例を示す。（ａ）は、硫酸電解液で生成した
普通の陽極酸化皮膜を示す。母材としてのアルミ合金製
内燃機関用ピストンのスカート部１００にＳｉ粒１１１
・・・が分布し、そのうちの表面近傍のＳｉ粒１１２・・・が
陽極酸化皮膜１１３に悪影響を及ぼして、陽極酸化皮膜
１１３が全体的に凹凸となっている。Hereinafter, a method for forming an ordinary anodic oxide film will be described with reference to FIG. 6 as a comparative example. FIGS. 6A to 6C show comparative examples in which an ordinary anodic oxide film is formed on a skirt portion of a piston for an internal combustion engine. (A) shows a normal anodic oxide film formed with a sulfuric acid electrolytic solution. Si grains 111 are formed on the skirt portion 100 of the piston for an internal combustion engine made of an aluminum alloy as a base material.
Are distributed, of which Si grains 112 in the vicinity of the surface adversely affect the anodic oxide film 113, and the anodic oxide film 113 is entirely uneven.

【００２２】（ｂ）は、（ａ）の拡大図であり、たまた
ま表面に出ていたＳｉ粒１１５の部分には陽極酸化皮膜
を形成できずに大きな窪みＤ１となり、また、表面にご
く近いＳｉ粒１１６の部分には陽極酸化皮膜１１７が形
成できたけれども、膜厚は周囲の陽極酸化皮膜１１３と
比べると小さく、窪みＤ２ができている。すなわち、Ｓ
ｉを含むアルミニウム合金製ピストン１００を硫酸電解
液で陽極酸化処理をしても、平坦な陽極酸化皮膜１１３
が得られないことが分かった。また、硫酸電解液では、
微細な孔１１８・・・の孔径をｄ２とすると、ｄ２は一般
的に１５ｎｍ程度と小さいことが分かった。FIG. 2B is an enlarged view of FIG. 2A, in which an anodic oxide film cannot be formed on the portion of the Si particles 115 that happened to appear on the surface, resulting in a large depression D1. Although the anodic oxide film 117 was formed on the portion of the grain 116, the film thickness was smaller than that of the surrounding anodic oxide film 113, and a depression D2 was formed. That is, S
Even if the aluminum alloy piston 100 containing i is anodized with a sulfuric acid electrolyte, a flat anodic oxide film 113
Was not obtained. Also, in the sulfuric acid electrolyte,
When the diameter of the fine holes 118 is d2, it is found that d2 is generally as small as about 15 nm.

【００２３】（ｃ）は、液状の熱硬化性樹脂を微細な孔
１１８・・・に含浸させ、含浸した液状の熱硬化性樹脂を
加熱して硬化樹脂１１９・・・に変えた状態を示す。樹脂
は摩擦抵抗が小さいので、陽極酸化皮膜１１３，１１７
に硬化樹脂１１９・・・を含浸させることで、Ｓｉ系アル
ミニウム合金製ピストンがシリンダ内を高速で往復移動
するときの摺動抵抗は比較的小さくなる。(C) shows a state in which the liquid thermosetting resin is impregnated into the fine holes 118, and the impregnated liquid thermosetting resin is heated to be changed into the cured resin 119. . Since the resin has low frictional resistance, the anodic oxide films 113, 117
Is impregnated with the hardening resin 119..., The sliding resistance when the Si-based aluminum alloy piston reciprocates in the cylinder at high speed becomes relatively small.

【００２４】しかし、（ｂ）に示したように、陽極酸化
皮膜１１３に窪みＤ１，Ｄ２が発生して陽極酸化皮膜１
１３を平坦に生成することが困難であり、また、陽極酸
化皮膜１１３に発生した微細な孔１１８・・・の孔径ｄ２
が小さいので陽極酸化皮膜１１３に樹脂１１９を十分に
含有することができない。このため、陽極酸化皮膜１１
３に樹脂１１９を含浸させても摩擦抵抗を所望の値まで
小さくすることはできない。However, as shown in FIG. 2B, dents D1 and D2 are formed in the anodic oxide film 113, and
13 is difficult to form flat, and the diameter d2 of the fine holes 118...
Is small, so that the resin 119 cannot be sufficiently contained in the anodic oxide film 113. Therefore, the anodic oxide film 11
Even when the resin 3 is impregnated with the resin 119, the frictional resistance cannot be reduced to a desired value.

【００２５】以下、図４の断面拡大図に示した特殊な陽
極酸化皮膜を形成する方法を説明する。図７は本発明に
係るアルミ合金製内燃機関用ピストン（第１実施の形
態）の特殊な陽極酸化皮膜処理方法を説明するフローチ
ャートであり、図中ＳＴ××はステップ番号を示す。 ＳＴ１０；アルミ合金製内燃機関用ピストン（すなわ
ち、Ｓｉ系アルミニウム合金としてのＡＣ８Ｃアルミニ
ウム合金製ピストン）のスカート部の外表面を脱脂す
る。 ＳＴ１１；りん酸塩としてのりん酸３ナトリウム及びふ
っ化物としてのふっ化カリウムの混合水溶液中で電気分
解して、スカート部の外側表面に特殊な陽極酸化皮膜を
生成する。この陽極酸化皮膜の表面に微細な孔が生成す
る。Hereinafter, a method for forming the special anodic oxide film shown in the enlarged sectional view of FIG. 4 will be described. FIG. 7 is a flowchart for explaining a special anodic oxide film treatment method for an aluminum alloy internal combustion engine piston (first embodiment) according to the present invention, in which STxx indicates a step number. ST10: Degreasing the outer surface of the skirt of an aluminum alloy internal combustion engine piston (that is, an AC8C aluminum alloy piston as a Si-based aluminum alloy). ST11: Electrolyze in a mixed aqueous solution of trisodium phosphate as a phosphate and potassium fluoride as a fluoride to form a special anodic oxide film on the outer surface of the skirt. Fine pores are formed on the surface of the anodic oxide film.

【００２６】ＳＴ１２；ふっ素樹脂を含有する液状の熱
硬化性樹脂（ふっ素系樹脂）を準備し、この液状の熱硬
化性樹脂を陽極酸化皮膜の微細な孔に含浸させる。 ＳＴ１３；微細な孔に含浸した液状の熱硬化性樹脂を加
熱することにより硬化させる。これで、本発明に係るア
ルミニウム合金製ピストンの陽極酸化処理が完了する。 以下、Ｓｉ系アルミニウム合金の陽極酸化処理方法のＳ
Ｔ１０〜ＳＴ１３を図８〜図９で詳しく説明する。ST12: A liquid thermosetting resin (fluororesin) containing a fluororesin is prepared, and the liquid thermosetting resin is impregnated into fine pores of the anodic oxide film. ST13: The liquid thermosetting resin impregnated in the fine pores is cured by heating. This completes the anodizing treatment of the aluminum alloy piston according to the present invention. Hereinafter, S of the anodizing treatment method for Si-based aluminum alloy
T10 to ST13 will be described in detail with reference to FIGS.

【００２７】図８（ａ），（ｂ）は本発明に係るアルミ
合金製内燃機関用ピストン（第１実施の形態）の特殊な
陽極酸化皮膜処理方法の第１説明図である。（ａ）は、
ＳＴ１０（脱脂）後の状態を示す図であり、アルミ合金
製内燃機関用ピストンのスカート部２０の外表面２１ａ
を脱脂した状態を示す。スカート部２０の外表面２１ａ
の近傍にはアルミニウムにＳｉ粒５５，５６，５７が分
散している。FIGS. 8 (a) and 8 (b) are first explanatory views of a special anodic oxide film treatment method for an aluminum alloy internal combustion engine piston (first embodiment) according to the present invention. (A)
FIG. 9 is a view showing a state after ST10 (degreasing), and shows an outer surface 21a of a skirt portion 20 of an aluminum alloy internal combustion engine piston.
Degreased state. Outer surface 21a of skirt portion 20
Are dispersed in the vicinity of the aluminum particles 55, 56, 57 in aluminum.

【００２８】（ｂ）は、ＳＴ１１（特殊な陽極酸化皮膜
処理）後の状態を示す図であり、りん酸３ナトリウム及
びふっ化カリウムの混合水溶液中で電気分解して陽極酸
化皮膜５０を生成した状態を示す。 りん酸３ナトリウムの腐食作用でスカート部２０の外表
面２１ａ（（ａ）に示す）が溶解して、Ｓｉ粒５５，５
６，５７が露出する。露出したＳｉ粒５５，５６，５７
がふっ化カリウムの作用で溶解して小さくなる。(B) is a view showing a state after ST11 (special anodic oxide film treatment), in which an anodized film 50 is formed by electrolysis in a mixed aqueous solution of trisodium phosphate and potassium fluoride. Indicates the status. The outer surface 21a (shown in (a)) of the skirt portion 20 is dissolved by the corrosive action of trisodium phosphate, and the Si particles 55, 5
6, 57 are exposed. Exposed Si grains 55, 56, 57
Is dissolved and reduced by the action of potassium fluoride.

【００２９】このため、スカート部２０の外表面２１ａ
にＳｉ粒５５，５６，５７が存在するにも拘らず、陽極
酸化皮膜５０が良好に成長する。この結果、陽極酸化皮
膜５０の皮膜面２１が揃うので、面粗度は小さくなり、
膜厚ｔ３はほぼ一定となる。また、電解液にはりん酸３
ナトリウムを含むため、りん酸３ナトリウムの孔径を大
きくする作用で、微細な孔５２・・・の孔径ｄ１は略１０
０ｎｍと十分に大きくなる。For this reason, the outer surface 21a of the skirt portion 20
The anodic oxide film 50 grows favorably despite the presence of the Si grains 55, 56, 57 at the bottom. As a result, since the coating surface 21 of the anodic oxide coating 50 is aligned, the surface roughness is reduced,
The thickness t3 is almost constant. In addition, phosphoric acid 3
Since it contains sodium, the pore diameter d1 of the fine pores 52 is approximately 10 by the action of increasing the pore diameter of trisodium phosphate.
It becomes sufficiently large as 0 nm.

【００３０】図９（ａ），（ｂ）は本発明に係るアルミ
合金製内燃機関用ピストン（第１実施の形態）の特殊な
陽極酸化皮膜処理方法の第２説明図である。（ａ）は、
ＳＴ１２（樹脂含浸処理）後の状態を示す図であり、ふ
っ素樹脂を含有する液状の熱硬化性樹脂５３を準備し、
この液状の熱硬化性樹脂５３を陽極酸化皮膜５０の孔５
２・・・に含浸した状態を示す。孔５２・・・の孔径ｄ１が１
００ｎｍと大きいので、多量の熱硬化性樹脂５３を孔５
２・・・内に含浸させることができる。なお、熱硬化性樹
脂５３は溶媒希釈しなくても液状をなす樹脂である。FIGS. 9A and 9B are second illustrations of a method for treating a special anodic oxide film on an aluminum alloy internal combustion engine piston (first embodiment) according to the present invention. (A)
FIG. 11 is a view showing a state after ST12 (resin impregnation processing), in which a liquid thermosetting resin 53 containing a fluororesin is prepared,
This liquid thermosetting resin 53 is applied to the holes 5 of the anodic oxide film 50.
2 show the impregnated state. The hole diameter d1 of the holes 52 is 1
00 nm, a large amount of thermosetting resin 53
2 ... can be impregnated. Note that the thermosetting resin 53 is a resin that is in a liquid state without being diluted with a solvent.

【００３１】（ｂ）は、ＳＴ１３（樹脂硬化処理）後の
状態を示す図であり、オーブンのコイル５８から矢印の
如く熱を伝えることにより液状の熱硬化性樹脂５３を加
熱する。液状の熱硬化性樹脂５３が硬化して熱硬化性樹
脂５４となる。これで、図４に示す特殊な陽極酸化皮膜
５０に熱硬化性樹脂５４を含浸させた状態になる。FIG. 3B is a view showing a state after ST13 (resin curing process), in which the liquid thermosetting resin 53 is heated by transmitting heat as indicated by an arrow from a coil 58 of an oven. The liquid thermosetting resin 53 is cured to form a thermosetting resin 54. Thus, the special anodic oxide film 50 shown in FIG. 4 is impregnated with the thermosetting resin 54.

【００３２】本発明によれば、りん酸３ナトリウムには
微細な孔５２・・・の孔径を大きくする作用がある。この
ため、陽極酸化皮膜５０の微細な孔５２・・・を大きな孔
径ｄ１にすることができる。従って、陽極酸化皮膜５０
に多量の熱硬化性樹脂５４を含浸することができ、且つ
含浸した熱硬化性樹脂５４を孔５２・・・内に確実に固着
することができる。この結果、摺動抵抗を減らすことが
でき、かつ耐久性を高めることができる。一方、ふっ化
カリウムにはＳｉを溶解する作用と増膜作用とがある。
このため、陽極酸化皮膜５０の皮膜面２１を平坦にする
ことができるので、摺動抵抗をより減らすことができ
る。According to the present invention, trisodium phosphate has the effect of increasing the diameter of the fine holes 52. Therefore, the fine holes 52 of the anodic oxide film 50 can have a large hole diameter d1. Therefore, the anodic oxide film 50
Can be impregnated with a large amount of the thermosetting resin 54, and the impregnated thermosetting resin 54 can be securely fixed in the holes 52. As a result, sliding resistance can be reduced and durability can be improved. On the other hand, potassium fluoride has a function of dissolving Si and a function of increasing the film thickness.
For this reason, since the coating surface 21 of the anodic oxide coating 50 can be made flat, the sliding resistance can be further reduced.

【００３３】さらに、熱硬化性樹脂５４に含有したふっ
素樹脂は、耐摩耗性や耐熱性に優れており、熱硬化性樹
脂５４を耐摩耗性や耐熱性に優れた樹脂にすることがで
きる。従って、熱硬化性樹脂５４を、例えば１００℃〜
３００℃以上の高温において使用することができるの
で、ピストンのような高温状態で使用する部材に好適で
ある。Further, the fluororesin contained in the thermosetting resin 54 is excellent in abrasion resistance and heat resistance, and the thermosetting resin 54 can be a resin excellent in abrasion resistance and heat resistance. Therefore, the thermosetting resin 54 is heated to, for example, 100 ° C.
Since it can be used at a high temperature of 300 ° C. or higher, it is suitable for a member used in a high temperature state such as a piston.

【００３４】[0034]

【実施例】本発明に係る実施例及び比較例を表１、表２
及び図１０、図１１に基づいて説明する。共通条件：供
試材 ＡＣ８Ｃ（ＪＩＳ Ｈ ５２０２ アルミニウム合
金鋳物）成分は表１に示すが、約１０％のＳｉを含む鋳
物である。Examples Examples and comparative examples according to the present invention are shown in Tables 1 and 2 below.
And FIG. 10 and FIG. Common conditions: Test material AC8C (JIS H5202 aluminum alloy casting) The components are shown in Table 1, and are castings containing about 10% Si.

【００３５】[0035]

【表１】 [Table 1]

【００３６】[0036]

【表２】 [Table 2]

【００３７】実施例：アルミ合金製内燃機関用ピストン
のスカート部の外表面を脱脂した後、０．４モル／ｌり
ん酸３ナトリウム及び０．１２５モル／ｌふっ化カリウ
ムの混合電解液で、電解液温度を２２℃、電圧を７０Ｖ
として３０分間電気分解して、スカート部の外表面に特
殊な陽極酸化皮膜を生成した。特殊な陽極酸化皮膜の微
細な孔は孔径ｄ１（図９（ａ）参照）が１００ｎｍと大
きく、陽極酸化皮膜の表面最大粗さＲｍａｘは２〜３μ
ｍと平坦である。なお、Ｒｍａｘは、ＪＩＳ Ｂ ０６０
１で定義する表面粗さの最大高さであるが、便宜上「表
面最大粗さＲｍａｘ」を表記した。Example: After the outer surface of the skirt of an aluminum alloy internal combustion engine piston was degreased, a mixed electrolytic solution of 0.4 mol / l trisodium phosphate and 0.125 mol / l potassium fluoride was used. Electrolyte temperature 22 ℃, voltage 70V
For 30 minutes to form a special anodic oxide film on the outer surface of the skirt. The fine pores of the special anodic oxide film have a large pore diameter d1 (see FIG. 9A) of 100 nm, and the maximum surface roughness Rmax of the anodic oxide film is 2-3 μm.
m and flat. In addition, Rmax is JIS B 060
Although it is the maximum height of the surface roughness defined by 1, the “surface maximum roughness Rmax” is described for convenience.

【００３８】次に、生成した陽極酸化皮膜を１０ｍｍＨ
ｇの減圧状態で、パーフロロオクチルエチルメタクレー
ト（熱硬化性樹脂）液中に５分間浸漬した後、大気開放
して９８℃の温水に１０分間浸漬した。温水から取り出
した後、オーブンで５分間加熱してパーフロロオクチル
エチルメタクレートを硬化した。この結果、面圧３０ｋ
ｇｆ／ｃｍ2で摩擦係数μを０．００６と小さくするこ
とができた。なお、摩擦係数μについては図１０のグラ
フで詳しく説明する。なお、パーフロロオクチルエチル
メタクレートの化学式は以下の通りである。Next, the formed anodic oxide film was
After immersion in a perfluorooctylethyl methacrylate (thermosetting resin) solution for 5 minutes under reduced pressure of g, the film was opened to the atmosphere and immersed in 98 ° C. hot water for 10 minutes. After removal from the warm water, the mixture was heated in an oven for 5 minutes to cure perfluorooctylethyl methacrylate. As a result, the surface pressure 30k
The coefficient of friction μ was reduced to 0.006 at gf / cm 2 . The coefficient of friction μ will be described in detail with reference to the graph of FIG. The chemical formula of perfluorooctylethyl methacrylate is as follows.

【００３９】[0039]

【化１】 Embedded image

【００４０】比較例：アルミ合金製内燃機関用ピストン
のスカート部の外表面を脱脂した後、１５％硫酸の電解
液で、電解液温度を０℃、電圧を１５Ｖとして２０分間
電気分解して、アルミニウム合金製ピストンの表面に普
通の陽極酸化皮膜を生成した。普通の陽極酸化皮膜の微
細な孔は孔径ｄ２（図６（ｂ）参照）が１５ｎｍと小さ
く、陽極酸化皮膜の表面最大粗さＲｍａｘは１２〜１３
μｍと凸凹である。Comparative Example: After the outer surface of the skirt portion of an aluminum alloy piston for an internal combustion engine made of aluminum alloy was degreased, it was electrolyzed with an electrolyte of 15% sulfuric acid at an electrolyte temperature of 0 ° C. and a voltage of 15 V for 20 minutes. An ordinary anodic oxide film was formed on the surface of the aluminum alloy piston. The fine pores of an ordinary anodic oxide film have a small hole diameter d2 (see FIG. 6B) of 15 nm, and the maximum surface roughness Rmax of the anodic oxide film is 12 to 13
μm and unevenness.

【００４１】次に、生成した陽極酸化皮膜を１０ｍｍＨ
ｇの減圧状態でパーフロロオクチルエチルメタクレート
液中に５分間浸漬した後、大気開放して９８℃の温水に
１０分間浸漬した。温水から取り出した後、オーブンで
５分間加熱してパーフロロオクチルエチルメタクレート
を硬化した。この結果、面圧３０ｋｇｆ／ｃｍ2で摩擦
係数μは０．０７であった。この摩擦係数μは実施例の
０．００６と比較して大きい。なお、摩擦係数μについ
ては図１０のグラフで詳しく説明する。Next, the formed anodic oxide film was
After immersion in perfluorooctylethyl methacrylate solution for 5 minutes under reduced pressure of g, the vessel was opened to the atmosphere and immersed in 98 ° C warm water for 10 minutes. After removal from the warm water, the mixture was heated in an oven for 5 minutes to cure perfluorooctylethyl methacrylate. As a result, the friction coefficient μ was 0.07 at a surface pressure of 30 kgf / cm 2 . This friction coefficient μ is larger than that of the example of 0.006. The coefficient of friction μ will be described in detail with reference to the graph of FIG.

【００４２】図１０は本発明に係るアルミ合金製内燃機
関用ピストン（第１実施の形態）の特殊な陽極酸化皮膜
の摩擦係数を示すグラフであり、縦軸は摩擦係数μを示
し、横軸は面圧ｋｇｆ／ｃｍ2を示す。実線は実施例の
グラフを示し、破線は比較例のグラフを示す。実施例お
いて、摩擦係数μは、面圧１０ｋｇｆ／ｃｍ2のとき
０．０１３、面圧２０ｋｇｆ／ｃｍ2のとき０．００
８、面圧３０ｋｇｆ／ｃｍ2のとき０．００６、面圧４
０ｋｇｆ／ｃｍ2のとき０．００８、面圧５０ｋｇｆ／
ｃｍ2のとき０．００６である。実施例によれば、面圧
が１０〜５０ｋｇｆ／ｃｍ2の範囲で摩擦係数μを０．
０１３以下に小さくすることができる。従って、摺動抵
抗を十分に減少させることができる。FIG. 10 is a graph showing the friction coefficient of a special anodic oxide film of the aluminum alloy internal combustion engine piston according to the present invention (first embodiment), wherein the vertical axis represents the friction coefficient μ and the horizontal axis. Indicates a surface pressure kgf / cm 2 . The solid line shows the graph of the example, and the broken line shows the graph of the comparative example. Keep embodiment, the μ friction coefficient 0.013 when the surface pressure 10 kgf / cm 2, when the surface pressure 20 kgf / cm 2 0.00
8, 0.006 when the contact pressure is 30 kgf / cm 2 , 4 contact pressure
0.008 at 0 kgf / cm 2 , surface pressure 50 kgf /
It is 0.006 at cm 2 . According to the embodiment, when the surface pressure is in the range of 10 to 50 kgf / cm 2 , the friction coefficient μ is set to 0.1.
013 or less. Therefore, the sliding resistance can be sufficiently reduced.

【００４３】一方、比較例において、摩擦係数μは、面
圧１０ｋｇｆ／ｃｍ2のとき０．０６、面圧２０ｋｇｆ
／ｃｍ2のとき０．０６９、面圧３０ｋｇｆ／ｃｍ2のと
き０．０６９、面圧４０ｋｇｆ／ｃｍ2のとき０．０６
２、面圧５０ｋｇｆ／ｃｍ2のとき０．０５４である。
比較例によれば、面圧が１０〜５０ｋｇｆ／ｃｍ2の範
囲で摩擦係数μは０．０５４以上になり、実施例の摩擦
係数μ０．０１３より大きくなる。従って、摺動抵抗を
十分に減少させることはできない。On the other hand, in the comparative example, the friction coefficient μ was 0.06 when the surface pressure was 10 kgf / cm 2 and the surface pressure was 20 kgf / cm 2.
When / cm 2 0.069, 0.069 when the surface pressure of 30kgf / cm 2, 0.06 when the surface pressure of 40kgf / cm 2
2, 0.054 when the surface pressure is 50 kgf / cm 2 .
According to the comparative example, when the surface pressure is in the range of 10 to 50 kgf / cm 2 , the friction coefficient μ is 0.054 or more, which is larger than the friction coefficient μ0.013 of the example. Therefore, the sliding resistance cannot be sufficiently reduced.

【００４４】図１１（ａ），（ｂ）は本発明に係るアル
ミ合金製内燃機関用ピストンの特殊な陽極酸化皮膜を説
明する断面図であり、（ａ）は表１の比較例、（ｂ）は
表１の実施例を示す。（ａ）は、アルミ合金製内燃機関
用ピストン１２０のスカート部１２１に条痕１２２を形
成し、条痕１２２に普通の陽極酸化皮膜１２３を形成
し、陽極酸化皮膜１２３の微細な孔に潤滑剤を含浸させ
た状態を示す。FIGS. 11 (a) and 11 (b) are cross-sectional views for explaining a special anodic oxide film of the aluminum alloy internal combustion engine piston according to the present invention. FIG. 11 (a) is a comparative example of Table 1, and FIG. ) Shows the examples in Table 1. (A) shows a case in which a streak 122 is formed on a skirt portion 121 of a piston 120 for an internal combustion engine made of an aluminum alloy, an ordinary anodic oxide film 123 is formed on the streak 122, and a lubricant is provided in fine holes of the anodic oxide film 123. Is impregnated.

【００４５】普通の陽極酸化処理ではスカート部１２１
の表面にＳｉがあると陽極酸化皮膜１２３の形成を阻止
して、陽極酸化皮膜１２３を平坦に形成することができ
ない。このため、陽極酸化皮膜１２３を条痕１２２の形
状に倣わせることができないので、陽極酸化皮膜１２３
の表面形状は条痕１２２の表面形状と異なる。加えて、
陽極酸化皮膜１２３の凹部深さＨ２は条痕１２２の凹部
深さＨと比較して小さくなる。従って、条痕１２２と同
じ量の油膜を陽極酸化皮膜１２３の表面に保持すること
ができないので、アルミ合金製内燃機関用ピストン１２
０の摺動抵抗を十分に低減して燃費の向上を図ることが
できない。In the ordinary anodic oxidation treatment, the skirt portion 121 is used.
If there is Si on the surface, the formation of the anodic oxide film 123 is prevented, and the anodic oxide film 123 cannot be formed flat. For this reason, the anodic oxide film 123 cannot follow the shape of the streak 122, and
Is different from the surface shape of the streak 122. in addition,
The recess depth H2 of the anodic oxide film 123 is smaller than the recess depth H of the streak 122. Therefore, the same amount of oil film as the streak 122 cannot be retained on the surface of the anodic oxide film 123, and the piston 12
Thus, the sliding resistance of 0 cannot be sufficiently reduced to improve fuel efficiency.

【００４６】（ｂ）は、アルミ合金製内燃機関用ピスト
ン１０のスカート部２０に条痕２２を形成し、条痕２２
に特殊な陽極酸化皮膜５０を形成し、陽極酸化皮膜５０
の微細な孔に潤滑剤を含浸させた状態を示す。特殊な陽
極酸化処理は、電解液にりん酸塩並びにふっ化物を混合
することで、Ｓｉを溶かして陽極酸化皮膜５０を平坦に
形成することができる。これで、陽極酸化皮膜５０を条
痕２２の形状に倣わせて形成して、陽極酸化皮膜５０の
表面を条痕２２と略同じ形状にすることができる。(B) shows a case in which a streak 22 is formed on the skirt portion 20 of the piston 10 for an aluminum alloy internal combustion engine.
A special anodic oxide film 50 is formed on the
3 shows a state in which a fine pore is impregnated with a lubricant. In a special anodic oxidation treatment, a phosphate and a fluoride are mixed into an electrolytic solution to dissolve Si and form the anodic oxide film 50 flat. Thus, the anodic oxide film 50 can be formed so as to follow the shape of the streaks 22, and the surface of the anodic oxide film 50 can be made substantially the same shape as the streaks 22.

【００４７】このため、陽極酸化皮膜５０の凹部深さＨ
３は、条痕２２の凹部深さＨと略同じになる。加えて、
陽極酸化皮膜５０の凹部５１は深さが不均一なので、ス
カート部２０全体に十分な油膜を均一に保持することが
できる。加えて、りん酸塩には陽極酸化皮膜の微細な孔
の孔径を大きくする作用があるので、微細な孔に多量の
潤滑剤を含浸させ、その潤滑剤を孔内に確実に固着させ
る。従って、ピストン２０の摺動抵抗を低減することに
より燃費向上を図ることができる。Therefore, the depth H of the concave portion of the anodic oxide film 50
3 is substantially the same as the recess depth H of the streak 22. in addition,
Since the depth of the concave portion 51 of the anodic oxide film 50 is non-uniform, a sufficient oil film can be uniformly maintained over the entire skirt portion 20. In addition, since phosphate has an effect of increasing the diameter of the fine pores of the anodic oxide film, a large amount of lubricant is impregnated into the fine pores, and the lubricant is securely fixed in the pores. Therefore, fuel economy can be improved by reducing the sliding resistance of the piston 20.

【００４８】次に、第２実施の形態および第３実施の形
態について説明する。なお、第１実施の形態と同一部材
については同一符号を付して説明を省略する。図１２は
本発明に係るアルミ合金製内燃機関用ピストン（第２実
施の形態）の側面図である。アルミ合金製内燃機関用ピ
ストン６０は、ピンボス部３５の下端３６及びピンボス
部３７の下端３８を一対のスカート部６２（奥側のスカ
ート部は図示しない）の下端６３よりδ寸法延したもの
である。このため、一対のスカート部６２を、第１実施
の形態のスカート部２０，２５より小さくすることがで
きる。従って、アルミ合金製内燃機関用ピストン６０を
よりアルミ合金製内燃機関用ピストン１０より軽量にす
ることができる。Next, a second embodiment and a third embodiment will be described. The same members as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. FIG. 12 is a side view of an aluminum alloy internal combustion engine piston (second embodiment) according to the present invention. In the piston 60 for an aluminum alloy internal combustion engine, the lower end 36 of the pin boss 35 and the lower end 38 of the pin boss 37 extend δ from the lower ends 63 of the pair of skirts 62 (the skirt on the back side is not shown). . For this reason, the pair of skirt portions 62 can be made smaller than the skirt portions 20 and 25 of the first embodiment. Therefore, the aluminum alloy internal combustion engine piston 60 can be made lighter than the aluminum alloy internal combustion engine piston 10.

【００４９】図１３は本発明に係るアルミ合金製内燃機
関用ピストン（第３実施の形態）の側面図である。アル
ミ合金製内燃機関用ピストン７０は、スカート部７２を
略逆台形、すなわち下端７３からピストン頭部７４に向
けてスカート幅をＷ３からＷ４に徐々に大きく形成した
ものである。スカート部７２を略逆台形に形成すること
により、スカート部７２の剛性を高めることができる。FIG. 13 is a side view of a piston (third embodiment) for an aluminum alloy internal combustion engine according to the present invention. The piston 70 for an aluminum alloy internal combustion engine has a skirt portion 72 having a substantially inverted trapezoidal shape, that is, a skirt width gradually increasing from W3 to W4 from the lower end 73 toward the piston head 74. By forming the skirt 72 in a substantially inverted trapezoidal shape, the rigidity of the skirt 72 can be increased.

【００５０】なお、前記実施の形態では、りん酸塩とし
てりん酸３ナトリウムを使用した例を示したが、その他
にりん酸ナトリウムなどを使用してもよい。また、ふっ
化物としてふっ化カリウムを使用した例を示したが、そ
の他にふっ化ナトリウムなどを使用してもよく、アルカ
リ金属系ふっ化物であれば同等の作用効果がある。In the above-described embodiment, an example in which trisodium phosphate is used as the phosphate is described. However, sodium phosphate or the like may be used instead. Further, although an example in which potassium fluoride is used as the fluoride has been described, sodium fluoride or the like may be used in addition to the above, and an alkali metal-based fluoride has the same effect.

【００５１】さらに、液状の熱硬化性樹脂としてパーフ
ロロオクチルエチルメタクレート液を使用した例を説明
したが、ふっ素を含んだその他の熱硬化性樹脂を使用し
てもよい。また、潤滑剤として熱硬化性樹脂を使用した
例を説明したが、光硬化性樹脂などのその他の樹脂を使
用しても同様の効果を得ることができる。光硬化性樹脂
は、例えば紫外線硬化性樹脂や可視光硬化性樹脂が該当
する。さらに、前記実施の形態では、条痕２２の凹部を
略台形に形成した例について説明したが、その他に条痕
の凹部を湾曲形などに形成してもよく、凹部の形状は任
意である。Further, an example has been described in which a perfluorooctylethyl methacrylate liquid is used as the liquid thermosetting resin, but other thermosetting resins containing fluorine may be used. Further, although an example in which a thermosetting resin is used as the lubricant has been described, similar effects can be obtained by using another resin such as a photocurable resin. The photocurable resin is, for example, an ultraviolet curable resin or a visible light curable resin. Further, in the above-described embodiment, the example in which the concave portion of the streak 22 is formed in a substantially trapezoidal shape is described. However, the concave portion of the streak may be formed in a curved shape or the like, and the shape of the concave portion is arbitrary.

【００５２】[0052]

【発明の効果】本発明は上記構成により次の効果を発揮
する。請求項１は、電解液にりん酸塩並びにふっ化物を
混合することで、Ｓｉを溶かして陽極酸化皮膜を平坦に
形成することができる。これで、陽極酸化皮膜を条痕の
形状に倣わせて形成して、陽極酸化皮膜の表面を条痕と
略同じ形状にすることができる。このため、スカート部
の条痕と同じ量の油膜を陽極酸化皮膜の表面に保持する
ことができる。加えて、りん酸塩には陽極酸化皮膜の微
細な孔の孔径を大きくする作用があるので、微細な孔に
多量の潤滑剤を含浸させ、その潤滑剤を孔内に確実に固
着させる。従って、ピストンの摺動抵抗を十分に低減さ
せて燃費向上を図ることができる。According to the present invention, the following effects are exhibited by the above configuration. According to the first aspect, by mixing a phosphate and a fluoride into the electrolytic solution, Si can be dissolved to form a flat anodic oxide film. Thus, the surface of the anodic oxide film can be formed to have substantially the same shape as the striation by forming the anodic oxide film according to the shape of the striation. For this reason, the same amount of oil film as the streak of the skirt portion can be held on the surface of the anodic oxide film. In addition, since phosphate has an effect of increasing the diameter of the fine pores of the anodic oxide film, a large amount of lubricant is impregnated into the fine pores, and the lubricant is securely fixed in the pores. Therefore, it is possible to sufficiently reduce the sliding resistance of the piston and improve the fuel efficiency.

【００５３】請求項２は、潤滑剤としてふっ素系樹脂を
採用した。ふっ素系樹脂は耐摩耗性や耐熱性に優れてお
り、ピストンのような高温状態で使用する部材に使用す
ることにより、ピストンの品質を高めることができる。The second aspect employs a fluororesin as a lubricant. Fluorine-based resin is excellent in wear resistance and heat resistance, and the quality of the piston can be improved by using it for a member used in a high temperature state such as a piston.

【図面の簡単な説明】[Brief description of the drawings]

【図１】本発明に係るアルミ合金製内燃機関用ピストン
（第１実施の形態）の斜視図FIG. 1 is a perspective view of an aluminum alloy internal combustion engine piston according to the present invention (first embodiment).

【図２】図１の２矢視図FIG. 2 is a view taken in the direction of arrow 2 in FIG. 1;

【図３】図１の３矢視図FIG. 3 is a view taken in the direction of arrow 3 in FIG. 1;

【図４】本発明に係るアルミ合金製内燃機関用ピストン
の特殊な陽極酸化皮膜の表面を拡大した断面図FIG. 4 is an enlarged sectional view of the surface of a special anodic oxide film of the piston for an aluminum alloy internal combustion engine according to the present invention.

【図５】図３の５−５線断面図FIG. 5 is a sectional view taken along line 5-5 in FIG. 3;

【図６】内燃機関用ピストンのスカート部に普通の陽極
酸化皮膜を形成した比較例FIG. 6 is a comparative example in which an ordinary anodic oxide film is formed on a skirt portion of a piston for an internal combustion engine.

【図７】本発明に係るアルミ合金製内燃機関用ピストン
（第１実施の形態）の特殊な陽極酸化皮膜処理方法を説
明するフローチャートFIG. 7 is a flowchart for explaining a special anodic oxide film treatment method for an aluminum alloy internal combustion engine piston (first embodiment) according to the present invention.

【図８】本発明に係るアルミ合金製内燃機関用ピストン
（第１実施の形態）の特殊な陽極酸化皮膜処理方法の第
１説明図FIG. 8 is a first explanatory view of a special anodic oxide film treatment method for an aluminum alloy internal combustion engine piston (first embodiment) according to the present invention.

【図９】本発明に係るアルミ合金製内燃機関用ピストン
（第１実施の形態）の特殊な陽極酸化皮膜処理方法の第
２説明図FIG. 9 is a second explanatory view of a method for treating a special anodic oxide film on an aluminum alloy internal combustion engine piston (first embodiment) according to the present invention.

【図１０】本発明に係るアルミ合金製内燃機関用ピスト
ン（第１実施の形態）の特殊な陽極酸化皮膜の摩擦係数
を示すグラフFIG. 10 is a graph showing a friction coefficient of a special anodic oxide film of an aluminum alloy internal combustion engine piston according to the present invention (first embodiment).

【図１１】本発明に係るアルミ合金製内燃機関用ピスト
ンの特殊な陽極酸化皮膜を説明する断面図FIG. 11 is a sectional view for explaining a special anodic oxide film of the aluminum alloy internal combustion engine piston according to the present invention.

【図１２】本発明に係るアルミ合金製内燃機関用ピスト
ン（第２実施の形態）の側面図FIG. 12 is a side view of an aluminum alloy internal combustion engine piston (second embodiment) according to the present invention.

【図１３】本発明に係るアルミ合金製内燃機関用ピスト
ン（第３実施の形態）の側面図FIG. 13 is a side view of an aluminum alloy internal combustion engine piston (third embodiment) according to the present invention.

【図１４】従来の内燃機関用ピストンのスカート部の断
面図FIG. 14 is a sectional view of a skirt portion of a conventional piston for an internal combustion engine.

【符号の説明】[Explanation of symbols]

１０，６０，７０…アルミ合金製内燃機関用ピストン、
２０，２５，６２，７２…スカート部、２１ａ…外表
面、２１…皮膜面、２２…条痕、５０…陽極酸化皮膜、
５２…微細な孔、５４…潤滑剤。10, 60, 70 ... piston for internal combustion engine made of aluminum alloy,
20, 25, 62, 72 ... skirt portion, 21a ... outer surface, 21 ... film surface, 22 ... streak, 50 ... anodized film,
52: fine holes, 54: lubricant.

───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.7 識別記号 ＦＩ テーマコート゛(参考） Ｆ１６Ｊ 1/08 Ｆ１６Ｊ 1/08 (72)発明者 丸井 勇治 埼玉県和光市中央１丁目４番１号 株式会 社本田技術研究所内 Ｆターム(参考） 3J044 AA12 AA20 BA04 BB11 BB14 BB26 BB40 BC04 DA09 ──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. 7 Identification symbol FI Theme coat ゛ (Reference) F16J 1/08 F16J 1/08 (72) Inventor Yuji Marui 1-4-1 Chuo, Wako-shi, Saitama Stock F term in Honda R & D Co., Ltd. (reference) 3J044 AA12 AA20 BA04 BB11 BB14 BB26 BB40 BC04 DA09

Claims (2)

【特許請求の範囲】[Claims] 【請求項１】 スカート部の外表面に条痕を形成したア
ルミ合金製内燃機関用ピストンであって、 前記スカート部の外表面に、りん酸塩並びにふっ化物を
混合した電解液で陽極酸化皮膜を被せ、この陽極酸化皮
膜の微細な孔に潤滑剤を含浸させたことを特徴とするア
ルミ合金製内燃機関用ピストン。1. A piston for an aluminum alloy internal combustion engine having a streak formed on an outer surface of a skirt portion, wherein an anodic oxide film is formed on the outer surface of the skirt portion by using an electrolytic solution containing a mixture of phosphate and fluoride. A piston for an internal combustion engine made of an aluminum alloy, wherein a lubricant is impregnated in fine pores of the anodic oxide film. 【請求項２】 前記潤滑剤はふっ素系樹脂であることを
特徴とする請求項１記載のアルミ合金製内燃機関用ピス
トン。2. The aluminum alloy internal combustion engine piston according to claim 1, wherein said lubricant is a fluororesin.
JP2000089757A 2000-03-28 2000-03-28 Internal combustion engine piston made of aluminum alloy Pending JP2001279495A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2000089757A JP2001279495A (en) 2000-03-28 2000-03-28 Internal combustion engine piston made of aluminum alloy

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2000089757A JP2001279495A (en) 2000-03-28 2000-03-28 Internal combustion engine piston made of aluminum alloy

Publications (1)

Publication Number Publication Date
JP2001279495A true JP2001279495A (en) 2001-10-10

Family

ID=18605464

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2000089757A Pending JP2001279495A (en) 2000-03-28 2000-03-28 Internal combustion engine piston made of aluminum alloy

Country Status (1)

Country Link
JP (1) JP2001279495A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010090812A (en) * 2008-10-08 2010-04-22 Art Metal Mfg Co Ltd Method for surface treatment of skirt section of piston for internal combustion engine and piston for internal combustion engine
CN101280447B (en) * 2007-04-07 2011-03-09 山东滨州渤海活塞股份有限公司 Automatic hard anodic oxidation device for aluminum piston ring groove
US8789509B2 (en) 2009-03-17 2014-07-29 Hitachi Automotive Systems, Ltd. Piston for internal combustion engine and piston surface treatment method

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101280447B (en) * 2007-04-07 2011-03-09 山东滨州渤海活塞股份有限公司 Automatic hard anodic oxidation device for aluminum piston ring groove
JP2010090812A (en) * 2008-10-08 2010-04-22 Art Metal Mfg Co Ltd Method for surface treatment of skirt section of piston for internal combustion engine and piston for internal combustion engine
US8789509B2 (en) 2009-03-17 2014-07-29 Hitachi Automotive Systems, Ltd. Piston for internal combustion engine and piston surface treatment method

Similar Documents

Publication Publication Date Title
JP2005504884A (en) Anodized magnesium or magnesium alloy piston and method of manufacturing the same
EP0937889B1 (en) Reciprocating engine having an aluminum engine block and an aluminum piston
KR100981898B1 (en) Cylinder liner and method for manufacturing the same
JP4898659B2 (en) High strength steel cylinder liner for diesel engine
JP4379852B2 (en) Piston for internal combustion engine made of aluminum alloy
JP3751498B2 (en) Piston for internal combustion engine made of aluminum alloy
JP2001279495A (en) Internal combustion engine piston made of aluminum alloy
JP2000328292A (en) Anodic oxidation treatment of si-base aluminum alloy
JP2003013799A (en) Aluminum alloy-made piston for internal combustion engine and its manufacturing method
JP2006144574A (en) Piston
CN100419590C (en) Metal belt and coating belt
JP4256050B2 (en) Piston for internal combustion engine made of aluminum alloy and method for manufacturing the same
JP2001263157A (en) Aluminum alloy piston for internal combustion engine
JP2003013801A (en) Manufacturing method of aluminum alloy-made piston for internal combustion engine
JP2001227408A (en) Aluminum alloy piston for internal combustion engine
JP2001271704A (en) Piston made of aluminum alloy for internal combustion engine
JP4595836B2 (en) Bore lower end structure of cylinder block and thermal spray coating forming method
JP5190473B2 (en) COMPOSITION FOR MULTILAYER LUBRICATION COATING AND PISTON FOR INTERNAL COMBUSTION ENGINE
JP2010255038A (en) Surface treatment method and sliding member
JP2004043730A (en) Part for sliding with lubricative film
JP2001192891A (en) Aluminum alloy parts and producing method therefor
JP2836926B2 (en) piston ring
JP5719839B2 (en) Slide member with exposed functional surface
JPH07117104B2 (en) Combination sliding member
JP2005201099A (en) Piston and cylinder for internal combustion engine